Vibrating and tamping devices



Sept. 27, 1966 K. HAAGE VIBRATING AND TAMPING DEVICES 2 Sheets-Sheet 1Filed Aug. 9, 1963 IIIIIIIIIIII Sept. 27, 1966 K. HAAGE 3,274,907

VIBRATING AND TAMPING DEVICES Filed Aug. 9, 1963 2 Sheets-Sheet 2 UnitedStates Patent Ofiice 3,274,907 Patented Sept. 27, 1966 3,274,907VIBRATING AND TAMPING DEVICES Konrad Haage, Esslingen-Kimmichsweiler,Germany, as-

signor to Heusser-Delmag A.G., Cham-Zg, Switzerland Filed Aug. 9, 1963,Ser. No. 301,151 Claims priority, application Germany, Aug. 16, 1962, D39,630 11 Claims. (Cl. 9448) The present invention relates to vibratingand tamping devices used for compacting masses such as earth used forbuilding foundations, roadways, said, concrete, etc.

Conventional devices of this type have rotary, unbalanced weights whichdue to their centrifugal force cause the devices to rise up from themass and to fall back down on the same and also these forces havehorizontal components which cause the device to advance itself withrespect to the mass which is being worked on. Devices of this type,however, have such complex vibration systems that it is impossible tocalculate in advance the exact manner of operation of the device inactual practice, so that as a result the behavior of the device inactual practice is to an undesirable extent unpredictable. Furthermore,it frequently happens that the known devices rise so high into the airduring one revolution of the rotary unbalanced weights thereof thatthese weights continue on the next revolution and change the directionof movement of the device before the latter engages the mass which is tobe compacted, so that the energy which should be applied to the masswhich is being worked on is instead simply applied to the free air.

There are also certain known tamping devices which have tamping weightswhich alternately engage the mass which is worked on one of the weightsrising while the other engages the mass and vice versa, but thedifliculty with these devices is that when they encounter the irregularsurface of roadways, sand piles, etc., these devices very frequently gethung up on one of the weights while the other weight simply turns in thefree air and thus the device cannot continue to operate unless it isdislodged. Also, the tamping force provided from such devices are notvery great and are not always distributed in the most desirable manner.In addition, it is not possible to obtain with devices of this type morethan 120 beats per minute, so that a suitable vibration cannot beobtained. For this purpose it should be possible to provide a beat rateon the order of 10003000 beats per minute.

Of course, there are known devices which have hydraulically orpneumatically operated pistons for adjusting the vertical and horizontalmovements of the vibrating device, but devices of this type areextremely complex and expensive.

It is accordingly a primary object of the present invention to provide avibrating and tamping device which avoids all of the above drawbacks.Thus, the objects of the invention include the provision of a device ofrelativelysimple and inexpensive construction which will be able tooperate with a relatively high number of beats per minute while at thesame time reliably making contact with the mass which is worked on onceduring each revolution of the crank shafts of the device.

Furthermore, it is an object of the invention to provide a device whichcan be used for vibrating purposes and which can then be used fortamping purposes simply by changing the speed of rotation of the crankmeans of the device.

It is furthermore an object of the invention to provide a device of theabove type which requires no springcushioned vibratory masses so that itis relatively simple to calculate in advance the behavior of the deviceof the invention and in addition its construction is considerablysimplified.

In fact, it is an object of the invention to provide a device of theabove type wherein all of the moving parts are coupled together in sucha way that they are all compelled to move with respect to each other ina predetermined manner.

It is furthermore an object of the present invention to provide a deviceof the above type which will automati cally adapt itself to the natureof the mass which is being worked on so that its manner of operationwill automatically respond to the nature of the material in such a waythat materials which are already in a highly compacted condition willnot be compacted much more while loosely compacted masses will be workedon to a greater extent in a fully automatic manner by the device of theinvention.

It is also an object of the present invention to provide a device of theabove type which will move along the material which is being worked onat a uniform rate, in contrast to known structures where the knowndevice stops and starts its movement with respect to the mass which isbeing worked on, and furthermore the objects of the present inventioninclude the provision of a device of the above type which will moverelatively quickly along a mass which is highly compacted and moreslowly, in a fully automatic manner, upon masses which are looselycompacted, so that in automatic response to the nature of the materialwhich is worked on the device of the invention will provide the bestpossible treatment.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

FIG. 1 is a partly schematic, partly sectional side view of one possibleconstruction of a vibrating and tamping device according to the presentinvention;

FIG. 2 is a transverse sectional view taken along line 2-2 of FIG. 1 inthe direction of the arrows but omitting the driving engine which islocated at the upper part of the plane in which the section of FIG. 2 istaken; and

FIG. 3 is a diagrammatic illustration of the manner in which thestructure of the invention operates.

The entire assembly which forms the device of the invention includesessentially only three moving weights or masses. One of these movingweights or masses is formed by the working plate means 2 which has theform of an open-top container, this working plate rneans 2 having abottom wall which engages the mass which is to be compacted and having acontinuous side wall extending upwardly from the periphery of the bottomwall. The continuous side wall of the working plate means 2 has a pairof opposed parallel side wall portions which respectively receive crankpins of a pair of crank means of the invention. Thus, the structureincludes a pair of crank means 4a and 4b, and the crack means 4a has apair of outer coaxial crank pins 41a which are respectively received inmating openings in the pair of opposed parallel side wall portions ofthe working plate means 2, while the other crank means 4b, which isidentical with the crank means 4a, has a pair of outer coaxial crankpins 41b which are respectively received in mating openings in theopposed parallel side wall portions of the working plate means 2. Itwill be noted that the working plate means 2 is located at the lowestpart of the apparatus and has a continuous bottom wall which forms theonly part of the apparatus which engages the mass which is to hecompacted. Each crank means 4a and 4b includes a pair of spaced coaxialdiscs 42a, 42b respectively, rotatably mounted in openings formed in apair of opposed parallel side walls of a first support means 1, a pairof outer or first laterally projecting offset crank pins 41a, 41b,respectively, and a body portion, namely, a second or inner crank pin43a, 43b, respectively, connecting each pair of discs. The axis a of theouter or first crank pins is offset a distance r from the axis ofrotation b of the crank discs which constitutes also the axis ofrotation of the respective crank means. The body portion or inner crankpin of the crank means is 180 opposed to said outer crank pins andspaced a distance r on the opposite side of the axis of rotation b ofsaid crank discs. Thus, crank means 4a includes a pair of coaxial crankdiscs 42a which have their common axis coinciding with the axis ofrotation of the crank means 4a, and the pair of outer or first crankpins 4111 respectively have their common axis located at a distance rfrom the common axis of the crank discs 42a. In the same way, the crankmeans 4b which is identical with the crank means 4a has a pair ofcoaxial crank discs 42!) which have a common axis 11 forming the centralaxis of rotation of the crank means 412, and the common axis a of thepair of outer or first crank pins 41b are also spaced from the commonaxis b of the crank discs 42b by the distance r as is shown most clearlyin FIG. 2. These crank discs 42a and 421; are respectively supported forrotary movement in mating openings formed in a pair of opposed parallelside walls of an elongated channel member 1 which has a top wall fromopposite sides of which the side wall of the channel member extenddownwardly, so that the cross section of the channel member 1 has theconfiguration of an inverted U, and this channel member 1 forms a firstsupport means for the structure of the invention, this first supportmeans forming the second of the three principal masses of the vibratingand tamping devices of the invention. It will be noted that the channelmember or first support means 1 extends downwardly into and is receivedwithin the elongated open-top container which forms the working platemeans 2 and which latter constitutes second support means for supportingsaid first support means.

The pair of crank discs 42a are interconnected by way of an inner orsecond crank pin 43a which extends between and is fixed at its ends tothe pair of crank discs 42a, and in the same way the pair of crank discs42b are fixed to each other by a crank pin 4% identical with the crankpin 43a and extending between and fixed to the pair of discs 42b, shownmost clearly in FIGS. 1 and 2, and each of the pins 43a and 43bconstituting a second crank pin and having with respect to the axis 11of its crank means an axis c which is spaced therefrom by a distance r(FIG. 2), and furthermore the arrangement is such that for each crankmeans the axis of the crank pin 43a or 43b is displaced with respect tothe common axis of the outer crank pins 41a or 41b by an angulardistance 180 with respect to the axis of the crank means. The thirdprincipal mass of the device of the invention is formed by a balancingplate means 3 in the form of an elongated block of metal, for example,which is formed with a pair of parallel bores in the region of therespective ends thereof and through which the crank pins 43a and 43brespectively extend with a snug sliding fit. It will be noted that thebalancing plate means 3 is situated in the space enclosed within thechannel member or support means 1.

The pair of crank discs 42a and 42]) which are supported for rotation byone of the walls of the channel member or first support means 1 (theleft wall as viewed in FIG. 2) respectively fixedly carry a pair of ringgears 5a and 5b which are fixed coaxially to these crank discs, andthese ring gears 5a and 5b mesh with an intermediate gear 6 which issupported for rotation by the same side wall of the channel member 1, sothat in this way the several gears form a transmission means which isalso accommodated in the space within the channel member 1 and whichinterconnects the pair of crank means in such a way that they arecompelled to rotate in synchronism.

It will be seen, however, that in any event the balancing plate means 3because of its connection to the pair of crank pins 43a and 43b compellsthe pair of crank means 4a and 4b to rotate in synchronism. Thus, itwill be seen that the structure includes a pair of crank means 4a and 4bwhich are identical and which have at any given instant the samepositions relative to the first support means 1, so that the pair ofcrank pins 41a and 41b at one side of the assembly will at any giveninstant have the same positions relative to the axes of the pair ofcrank means while the pair of crank pins 43a and 43b will also have atany given instant the same relative positions with respect to the axesof the pair of crank means, but the positions of the axes of the crankpins 43a and 43b will always be displaced by with respect to thepositions of the crank pins 41a and 41b. These latter pins are connectedto the working plate means while the crank pins 43a and 43b areconnected to the balancing plate means 3, and of course the entirestructure is supported by the second support means 2.

In order to drive the structure the first support means 1 carries at itsupper surface a driving motor in the form of an internal combustionengine 8, in the illustrated example, and this motor or engine 8 issupported by way of springs 13 on a plate which is in turn separated byadditional springs 13 from the member 1, so that in this way the drivingmotor 8 is insulated from the remainder of the structure in such a waythat the motor 8 is protected against shocks. A transmission shaft 9 isconnected through universal joints on the one hand to the output ordrive shaft of the drive motor 8 and on the other hand to the input of areversible transmission assembly 7 the output gear 10 of which mesheswith the ring gear 5a which of course has its rotation transmittedthrough the gear 6 to the other ring gear 5b. It is pointed out thatthis arrangement is illustrated only by way of example and the outputgear of the transmission could just as well mesh with the ring gear 511or indeed the intermediate gear 6.

One end of the support means 1 is provided with a pair of eyes 11carrying a pivot pin on which one end of a guiding pole 12 is supported,and the operator by engaging the pole 12 can guide the direction inwhich the device of the invention moves.

During operation of the device the working plate means 2 is compelled tomove with the outer crank pins 41a and 4112 so that all parts of theworking plate means 2 describe circular paths which are the same as thecircles along which the outer crank pins 41a and 41b turn, these crankpins of course turning around the axes of the crank discs 42a and 4212.Thus, the working plate means 2 Interconnects the pair of crank means inmuch the same way that a pair of wheels of a locomotive areinterconnected by a connecting rod which is pivotally connected at itsends to such a pair of wheels with these ends of the connecting rodgoing around the axes of the pair of wheels while the connecting roditself moves around and around these axes. A substantially similarconnectlon of the working plate means 2 to the pair of crank means 4aand 4b is provided with the structure of the invention.

It will be seen that the balancing plate means 3 is connected by way ofthe crank pins 43a and 43b to the pair of crank means 4a and 412 so thateach part of the balanc ng plate means 3 will move along a circular pathduring rotation of the pair of crank pins 43a and 43b, and thesecircular paths of every part of the balancing plate means 3 willcorrespond to the circles along which the crank pins 43a and 43b turnrespectively around the pair of axes of the pair of crank means 4a and412. Thus, the balancing plate means 3 is connected to the pair of crankmeans in a manner similar to the working plate means 2. Because the pairof second crank pins 43a and 431) which are connected to the balancingplate means are displaced by 180 respectively around the axes of thepair of crank means 4a and 4b from the common axes of the outer or firstcrank pins 41a and 41b, the balancing plate means 3 is capable ofeliminating any free inertia forces which of course would be highlyundesirable. The weight of the working plate means 2. together with thefour outer crank pins 41a and 4117, On the one hand, as well as theweight of the balancing plate means 3 together with the crank pins 43aand 43b, on the other hand, have together with the radii r and r withrespect to each other such a relationship that the single center ofgravity of the pair of weights or plate means 2 and 3 does not changeits position during operation of the device with respect to the entiredevice of the invention. As is apparent from the drawing, the bodies 2and 3 are shaped in such a way that they can have unobstructed movementrelative to the support means 1. During use of the apparatus themovement of the bodies 1 and 2 with respect to each other is relativelysmall so that sealing of the 'bodies 1 and 2 relative to each other soas to prevent dust or dirt from entering into the structure of theinvention, by the use of suitable rubber rings, sealing sleeves, or thelike, is easily possible.

Assuming, for example, that the structure of the invention is working ona mass 14 which is substantially inelastic and can be compacted only toa small extent, then in such a case the speed of rotation of the crankmeans and the radius of the crank pins have with respect to each othersuch relationship that the height to which the device jumps from themass 14 is so great that the time required for one revolution of eachcrank means is the time required for the center of gravity of the entiredevice to rise up and fall back down to its initial position. The sizeof the radius r of each crank means and the speed of rotation thereofare chosen in such a way that the device jumps up away from the mass 14and again contacts the mass 14 after falling down when the outer crankpins 41a and 41b have angular positions a in advance of their bottomdead center positions, as indicated in FIG. 3. Thus, the working platemeans 2 will engage the mass 14 when the outer crank pins are in advanceof their bottom dead center positions by an angle of less than 90, andas a result of this operation there is provided a horizontal component Wfor the device and a predetermined vertical component W The size of theradius r and the speed of rotation 11 of the crank means will determinethe magnitude of the vector W shown in FIG. 3, and thus the verticalcomponent W will be equal to W sin a while the horizontal component Wwill be equal to W- cos a, as is apparent from FIG. 3.

During operation of the device the magnitude of the angle aautomatically adjusts itself according to the yieldability of the mass14 which is worked on, and when a change in the yieldability of thismass 14 is encountered the angle a will change until equilibrium isreached during which the angle at will remain the same throughout theoperation until the nature of the mass 14 again changes. Assuming, forexample, that the structure operates with a predetermined angle a andthat the mass 14 changes in such a way that it becomes softer or moreyieldable. As a result the extent to which the device jumps up from themass 14 diminishes because the working plate means 2 will press furtherinto the more yieldable mass when engaging the latter. As a result thetime required for the jumping up and falling back of the device becomessmaller with the result that the angle a by which the crank pins 41a and41b are in advance of their bottom dead center positions when the plate2 encounters the mass becomes greater. This increase in the magnitude ofthe angle 0:, however, brings with it an increase in the magnitude ofthe vertical component W so that as a result the extent to which thedevice jumps upwardly away from the mass increases. On the other hand,when the device encounters a harder, less yieldable mass, then the anglea will also change and will remain constant at the changed value.

During a reduction in the size of the angle a from 45 to 10 themagnitude of the vertical component W will drop to one quarter of thevalue which it has at an angle of a which is 45, and the verticalcomponent disappears or becomes zero when the angle a is zero. As aresult, the device of the invention can never jump so high from the masson which it is working that the working plate means 2 does not againengage the mass 14 during each revolution.

It is of distinct advantage that with the structure of the invention thehorizotal component and thus the speed with which the device travelsunder normal operating conditions on the mass in which it is workingbecomes greater as the magnitude of the angle a diminishes.

The reversible transmission 10 makes it possible to reverse thedirection of rotation of the crank means so that the device can be movedforwardly or rearwardly.

A further advantage of the structure of the invention as compared tothose structures which include rotary unbalanced weights is that thedevice of the invention advances along the mass which is being worked onwith a uniform speed.

The upwardly or downwardly directed inclinations in the surface ofroadways or the like which are worked on during road buildingoperations, for example, have no appreciable influence on the speed ofadvance of the structure of the invention since this speed depends onlyon the speed of rotation of the crank means.

All operations depend only on the speed with which the crank means arerotated and the size of the radius r The springs 13 associated with themotor 8 serve only to provide the motor 8 with a shock-free mounting.

At relatively low speeds of rotation of the crank means, the extent towhich the device of the invention jumps up from the mass on which it isworking increases according to the square of l/n, wherein n is the speedof rotation of each crank means, as the speed of rotation of each crankmeans diminishes and as the crank radius r increases, so that atrelatively low speeds of operation, which is to say speeds of rotationof each crank means, the vibrating device operates very eifectively as atamping device, and thus is highly suitable for the compacting ofcohesive, non-particulate masses.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofvibrating devices from the types described above.

While the invention has been illustrated and described as embodied invibrating and tamping devices, it is not intended to be limited to thedetails shown, since various modifications and structural changes may bemade without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a vibrating and tamping device for compacting a mass locatedbeneath the device, in combination, first support means; a pair ofrotary crank means, each of said rotary crank means including means forsupporting the respective crank means on said first support means; forrotation about a predetermined axis of rotation and first and secondcrank pins .angularly displaced from each other by about said axis ofrotation and the axes of said first and second crank pins beingrespectively parallel to said axis of rotation, said pair of rotarycrank means having at any given instant the same angular positionsrelative to said support means, during operation of the device, so thatat any given instant the angular position of said first crank pins withreference to the axes of rotation of the pair of crank means areidentical and said second crank pins of said pair of crank means alsohave respectively with respect to said axes of rotation identicalangular positions displaced by 180 about said axes of rotation withrespect to the positions of said first crank pins; working plate meansoperatively connected to said first crank pins for movement therewithand located at the lowest part of the device during operation thereof,said working plate means being the only part of the device which engagesthe mass which is worked on by the device and said first crank pinsrotatably mounted in said working plate means which latter constitutes asecond support means; and balancing plate means operatively connected toboth said second crank pins for movement with the latter forcounte-rbalancing the movement of said working plate means to eliminateinertia forces, said balancing plate means remaining at all times out ofengagement with the mass which is worked on by the device.

2. In a device as recited in claim 1, said working plate means being inthe form of an open-top container having a bottom, mass-engaging walland a continuous side wall extending upwardly from the periphery of saidbottom wall, said first support means being in the form of an elongatedchannel member having a top wall and a pair of side walls extendingdownwardly from said top wall into the interior of said working platemeans, said side walls of said first support means supporting said pairof rotary crank means for rotation, and said balancing plate means beinglocated between said side walls of said first support means as well asbetween said top wall of said first support means and said bottom wallof said working plate means.

'3. In a device as recited in claim 2, transmission means extendingbetween and operatively connected to said pair of crank means formaintaining the latter in synchronous rotation with respect to eachother, said transmission means also being accommodated within the spacebetween said side walls of said first support means.

4. In a device as recited in claim I, said pair of crank means, saidworking plate means, and said balancing plate means having with respectto each other a relationship which provides these elements with a commoncenter of gravity which remains stationary with respect to said firstsupport means during operation of the device.

5. In a vibrating and tampering device for compacting a mass locatedbeneath the device, in combination, first support means; a pair ofrotary crank means, each of said rotary crank means including means forsupporting the respective crank means on said first support means forrotation about a predetermined axis of rotation and first and secondcrank pins angularly displaced from each other by 180 about said axis ofrotation and the axes of said first and second crank pins beingrespectively parallel to said axis of rotation, said pair of rotarycrank means having at any given instant the same angular positionsrelative to said support means, during operation of' the device, so thatat any given instant the angular position of said first crank pins withreference to the axes of rotation of the pair of crank means areidentical and said second crank pins of said pair of crank means alsohave respectively with respect to said axes identical angular positionsdisplaced by 180 about said axes of rotation with respect to thepositions of said first crank pins; working plate means operativelyconnected to said first crank pins for movement therewith and located atthe lowest par-t of the device during operation thereof, said workingplate means being the only part of the device which engages the masswhich is worked on by the device, said working plate means having acontinuous bottom plate portion which engages the mass which is workedon by the device and said first crank pins rotatably mounted in saidworking plate means which latter constitutes a second support means; andbalancing plate means operatively connected to both said second crankpins for movement with the latter for counterbalancing the movement ofsaid working plate means to eliminate inertia forces, said balancingplate means remaining at all times out of engagement with the mass whichis worked on by the device.

6. In a vibrating and tamping device for compacting a mass locatedbeneath the device, in combination, first support means; a pair ofrotary crank means, each of said rotary crank means including means forsupporting the respective crank means on said first support means forrotation first about a predetermined axis of rotation and first andsecond crank pins angularly displaced from each other by 180 about saidaxis of rotation and the axes of said first and second crank pins beingrespectively parallel to said axis of rotation, said pair of rotarycrank means having at any given instant the same angular positionsrelative to said support means, during operation of the device, so thatat any given instant the angular position of said first crank pins withreference to the axes of rotation of the pair of crank means areidentical and said second crank pins of said pair of crank means alsohave respectively with respect to said axes of rotation identicalangular positions displaced by 180 about said axes of rotation withrespect to the positions of said first crank pins; working plate meansoperatively connected to said first crank pins for movement therewithand located at the lowest part of the device during operation thereof,said working plate means being the only part of the device which engagesthe mass which is worked on by the device and said first crank pinsrotatably mounted in said working plate means which latter constitutes asecond support means; balancing plate means operatively connected toboth said second crank pins for movement with the latter forcounterbalancing the movement of said working plate means to eliminateinertia forces, said balancing plate means remaining at all times out ofengagement with the mass which is worked on by the device; meansrotating said pair of crank means at a speed within a given range ofspeeds which together with the radial distances of said first crank pinsfrom said axes of rotation bring about engagement of said working platemeans with the mass when said first crank pins are respectively at anangle of ,less than in advance of their bottom dead center positions.

7. A vibrating and tamping device for compacting a mass located beneaththe device, comprising, in combination, first support means; a pair ofrotary crank means, each of said rotary crank means including means forsupporting the respective crank means on said first support means forrotation about a predetermined axis of rotation and first and secondcrank pins angularly displaced from each other by about said axis ofrotation and the axes of said first and second crank pins beingrespectively parallel to said axis of rotation; means coacting with saidpair of crank means for maintaining them respectively at the sameangular positions and for rotating them synchronously, so that at anygiven instant the angular position of said first crank pins withreference to the axes of rotation of the pair of crank means areidentical and said second crank pins of said pair of crank means alsorespectively have at any given instant with respect to said axes ofrotation identical angular positions displaced by 180 about said axes ofrotation with respect to the positions of said first crank pins; workingplate means operatively connected to said first crank pins for movementtherewith and located at the lowest part of the device during operationthereof, said working plate means being the only part of the devicewhich engages the mass which is worked on by the device and said firstcrank pins rotatably mounted in said working plate means which latterconstitutes a second support means; and balancing plate meansoperatively connected to both said second crank pins for movement withthe latter for counterbalancing the movement of said working plate meansto eliminate inertia forces, said balancing plate means remaining 9 atall times out of engagement with the mass which is worked on by saidworking plate means.

8. A vibrating and tamping device for compacting a mass located beneaththe device, comprising, in combination, first support means; a pair ofrotary crank means, each of said rotary crank means including means forsupporting the respective crank means on said first support means forrotation about a predetermined axis of rotation and first and secondcrank pins angularly displaced from each other by 180 about said axis ofrotation and the axes of said first and second crank pins beingrespectively parallel to said axis of rotation; drive means carried bysaid support means and operatively connected to said pair of rotarycrank means for rotating the latter while maintaining them respectivelyat the same angular positions relative to said support means, so that atany given inst-ant the angular position of said first crank pins withreference to the axes of rotation of the pair of crank means areidentical and said second crank pins of said pair of crank means alsohave with respect to said axes of rotation at any given instantidentical angular positions respectively displaced by 180 about saidaxes of rotation with respect to the positions of said first crank pins;working plate means operatively connected to said first crank pins formovement therewith and located at the lowest part of the device duringoperation thereof, said working plate means being the only pant of thedevice which engages the mass which is worked on by the device and saidfirst crank pins rotatably mounted in said working plate means whichlatter constitutes .a second support means; and balancing plate meansoperatively connected to both said second crank pins for movement withthe latter for counterbalancing the movement of said working plate meansto eliminate inertia forces, said balancing plate means remaining at alltimes out of engagement with the mass which is worked on by said workingplate means.

9. In a vibrating and tamping device for compacting a mass locatedbeneath the device, in combination, an elongated channel member having atop wall and a pair of parallel side walls extending downwardly fromsaid top wall; a first pair of coaxial, identical crank discs supportedfor rotation by said pair of side walls; a first inner crank pinextending between said side walls and fixed to said first pair of crankdiscs, the axis of said first inner crank pin being located at a givenradial distance from the common axis of said first crank discs; a secondpair of rotary crank discs coaxial with each other and identical withsaid first pair of crank discs, said second pair of crank discs alsobeing supported for rotation by said pair of side walls and having theircommon axis parallel to the common axis of said first pair of discs; asecond inner crank pin extending between said side Walls and fixed tosaid second inner pair of crank discs, the axis of said second crank pinbeing located from the common axis of said pair of second discs by thesame distance that the axis of said first inner crank pin is locatedfrom the common axis of said first pair of discs; a first pair of outercoaxial crank pins respectively fixed to said first pair of discs atouter faces thereof located at the exterior of said channel member, saidfirst pair of outer crank pins having their common axis located at agiven distance from the common axis of said first pair of discs anddisplaced by from the axis of said first inner crank pin; a second pairof outer crank pins having a common axis and respectively fixedlycarried by outer faces of said second pair of crank discs which arelocated at the exterior of said side walls of said channel member, thecommon axis of said second pair of outer crank pins being spaced fromthe common axis of said second pair of discs by the same distance thatthe common axis of said first pair of outer crank pins are located fromthe common axis of said first pair of discs, and the common axis of saidsecond pair of outer crank pins also being displaced by 180 about thecommon axis of said second pair of discs from the axis of said secondinner crank pin; an open-top working member having a bottom,mass-engaging wall and a continuous side wall extending upwardly fromthe periphery of said bottom wall and having a pair of opposed parallelportions respectively extending alongside of said pair of side walls ofsaid channel member and between which said pair of side walls of saidchannel member are located, said side Wall portions of said open-topmember being respectively formed with openings receiving all of saidouter crank pins whereby during rotation of said crank discs saidopen-top member will act on a mass therebeneath to vibrate and compactthe mass with said bottom wall thereof; and a balancing member locatedbetween said side Walls of said channel member and respectively formedwith a pair of bores which respectively receive said first and secondcrank pins, said balancing member counterbalancing said open-top memberto eliminate inertia forces while remaining at all times out ofengagement with the mass which is engaged by said bottom wall.

10. In a device as recited in claim 9, drive means carried by saidchannel member and operatively connected to at least one of said crankdiscs for rotating the latter.

11. In a device as recited in claim 9,, transmission meansinterconnecting the pair of rotary crank discs which are carried by oneof said side walls for compelling said crank discs to rotatesynchronously.

References Cited by the Examiner UNITED STATES PATENTS 2,084,983 6/1937Baily 94-48 X 2,908,206 10/1959 Malanson 94-49 FOREIGN PATENTS 700,97210/ 1940 Germany. 446,169 4/ 1936 Great Britain.

JACOB L. NACKENOFF, Primary Examiner.

1. IN A VIBRATING AND TAMPING DEVICE FOR COMPACTING A MASS LOCATEDBENEATH THE DEVICE, IN COMBINATION, FIRST SUPPORT MEANS; A PAIR OFROTARY CRANK MEANS, EACH OF SAID ROTARY CRANK MEANS INCLUDING MEANS FORSUPPORTING THE RESPECTIVE CRANK MEANS ON SAID FIRST SUPPORT MEANS; FORROTATION ABOUT A PREDETERMINED AXIS OF ROTATION AND FIRST AND SECONDCRANK PINS ANGULARLY DISPLACED FROM EACH OTHER BY 180* ABOUT SAID AXISOF ROTATION AND THE AXES OF SAID FIRST AND SECOND CRANK PINS BEINGRESPECTIVELY PARALLEL TO THE AXIS OF ROTATION, SAID PAIR OF ROTARY CRANKMEANS HAVING AT A GIVEN INSTANT THE SAME ANGULAR POSITIONS RELATIVE TOSAID SUPPORT MEANS, DURING OPERATION OF THE DEVICE, SO THAT AT ANY GIVENINSTANT THE ANGULAR POSITION OF SAID FIRST CRANK PINS WITH REFERENCE TOTHE AXES OF ROTATION OF THE PAIR OF CRANK MEANS ARE IDENTICAL AND SAIDSECOND CRANK PINS OF SAID PAIR OF CRANK MEANS ALSO HAVE RESPECTIVELYWITH RESPECT TO SAID AXES OF ROTATION IDENTICAL ANGULAR POSITIONSDISPLACED BY 180* ABOUT SAID AXES OF ROTATION WITH RESPECT TO THEPOSITIONS OF SAID FIRST CRANK PINS; WORKING PLATE MEANS OPERATIVELYCONNECTED TO SAID FIRST CRANK PINS FOR MOVEMENT THEREWITH AND LOCATED ATTHE LOWEST PART OF THE DEVICE DURING OPERATION THEREOF, SAID WORKINGPLATE MEANS BEING THE ONLY PART OF THE DEVICE WHICH ENGAGES THE MASSWHICH IS WORKED ON BY THE DEVICE AND SAID FIRST CRANK PINS ROTATABLYMOUNTED IN SAID WORKING PLATE MEANS WHICH LATTER CONSTITUTES A SECONDSUPPORT MEANS; AND BALANCING PLATE MEANS OPERATIVELY CONNECTED TO BOTHSAID SECOND CRANK PINS FOR MOVEMENT WITH THE LATTER FOR COUNTERBALANCINGTHE MOVEMENT OF SAID WORKING PLATE MEANS TO ELIMINATE INERTIA FORCES,SAID BALANCING PLATE MEANS REMAINING AT ALL TIMES OUT OF ENGAGEMENT WITHTHE MASS WHICH IS WORKED ON BY THE DEVICE.